This invention relates to the physical property measuring arts, and, more particularly, to apparatus for measuring the pulse repetition frequency of an astable oscillator in conjunction with the determination of the specific gravity of a gas.
There are many applications in which it is highly desirable to have means for easily and accurately determining the specific gravity of a gas. The term specific gravity defines the ratio of a density of any gas to the density of air where both gases are examined at standard conditions such as temperature and pressure. It has been determined, as described and claimed in the above mentioned related applications, that the pulse repetition frequency of an astable fluidic oscillator is related to the gas density and that the ratio of the pulse repetition frequency using the test gas as the working fluid and the pulse repetition frequency using air as the working fluid, given standard conditions, obtains the gas density.
In one specific application, the rapidly increasing cost of natural gas has inclined the industry to sell natural gas on the basis of its energy or caloric content. This approach requires a knowledge of the specific gravity of the natural gas as well as the constituents of the gas. The present invention finds particular use in such an application and comprises apparatus by which the pulse repetition frequency of a fluidic oscillator through which a test gas is passing is readily measured and displayed digitally along with the temperature and pressure of the test gas.
It is therefore a broad object of this invention to provide improved means for measuring the pulse repetition frequency of a fluidic oscillator along with the temperature and pressure of the motive gas.
It is another object of this invention to provide such apparatus which is simple and economical to fabricate.
It is yet another object of this invention to provide such apparatus which exhibits low power consumption and is therefore readily portable employing battery power.